1. Field of the Invention
The present invention relates to a stereo speaker system in which an acoustic filter is located between stereo speakers that cannot secure a sufficient volume of a rear cavity and connects between the stereo speakers to eliminate low frequency components outputted from the both speakers in the acoustic filter, thereby removing an air loading phenomenon caused by back-pressure and smoothly vibrating a vibrating plate to improve low frequency characteristic of stereo speakers.
2. Description of Related Art
It is increasingly common that various types of multimedia are replayed using a mobile communication terminal, and a speaker installed in a mobile communication terminal is rapidly being replaced by stereo speakers. When an MP3 is replayed by an MP3 phone or a broadcasting program is replayed by a DMB phone, stereo speakers provide an effect of replaying clearer and active audio.
A mobile communication terminal including stereo speakers secures a sufficient size rear cavity, thereby replaying low frequency audio with improved quality from the stereo speakers.
Currently, the size of a mobile communication terminal is reduced as much as possible so that a user easily carries the mobile communication terminal. Accordingly, when the stereo speakers are installed in a mobile communication terminal that becomes too slim, the mobile communication terminal cannot secure a sufficient volume of a rear cavity to guarantee the quality of low frequency audio replayed from stereo speakers. Stated another way, slim mobile communication terminals often have difficulty reproducing low frequency tones with great fidelity.
Particularly, in the case the volume of a rear cavity cannot be secured, the quality of low frequency audio is notably deteriorated due to back-pressure with respect to the stereo speakers in the case the low frequency audio is replayed on the stereo speakers.
To solve the problems, a method is worked out, in which an absorber is located between stereo speakers to absorb low frequency components of audio occurring in replaying low frequency audio and to control occurrence of the back-pressure. However, since an absorber can absorb low frequency components of specific frequency, there may be a trouble to continuously change an absorber corresponding to a low frequency component to be absorbed in order to absorb various low frequency components.
Accordingly, a model of stereo speakers of a new concept is acutely required, in which back-pressure with respect to stereo speakers can be controlled to improve low frequency characteristic of the stereo speakers in the case the low-pitched sound is outputted from stereo speakers not capable of securing a sufficient rear cavity.